Currencies like Monero and Bitcoin are created by computer codes, solving complex math problems. The process requires huge amount of computing power.

BENGALURU: Browser-based cryptocurrency mining has seen a rapid rise in recent months, with cybersecurity company Symantec reporting a 34% increase in the number of mobile apps incorporating the code to mine virtual currencies.

Crypto coins are not produced by any central authority such as RBI. These currencies like Monero and Bitcoin are created by computer codes, solving complex math problems. The process requires huge amount of computing power.

By incorporating a piece of code into a website, cyber crooks use the laptop or mobile device of the website’s visitors to ‘mine’ cryptocurrencies without their knowledge. The mining process can start quickly and quietly in the browser without anyone noticing.

“Indian websites with high traffic should take stock of this development,” said security researcher Indrajeet Bhuyan.

Though browser-based mining had been around since 2013, the activity seems to have exploded in the last few months of 2017 as the value of cryptocurrencies skyrocketed. “After many years of deathly silence, the catalyst appears to be the launch of a new browser-based mining service in Sept by Coinhive,” a Symantec report said.

The service offered by Coinhive allows website owners to use their code to harness the power of visitors’ hardware. “For instance, if there are 1,000 people who visit a ticket booking website, the owner of the website can earn money (cryptocurrency) using the CPU power of the 1,000 computers to mine,” Bhuyan said.

This is precisely what a Mumbai-based tech blogger used to monetise the views on his popular tech blog. “I ran the script for a week to check if it was profitable. I was able to mine Rs 1,300-worth of Monero in a week,” said the blogger, who did not want to be named.

“It is very easy to implement the code on any website and it is easy to start mining … This is profitable only when your website has millions of hits and traffic,” said the blogger, who claims to get about 6 lakh unique users a day.

Mining happens without the knowledge of the user and causes the device to heat-up and slow down. “Until a few months back, only when you open the website the script will run.

Now, new kinds of scripts are coming up where even if you close the website they still continue to use your computer hardware to mine,” Bhuyan said. “They hack websites, insert the scripts, and earn money.”

For instance, government websites like IRCTC have 10 million visitors a day to book tickets. Researchers say these websites act as a perfect platform to deploy ‘custom script’. A custom script is a special piece of code tailor-made to mine on specific websites. “The way to protect your device from this is through plugins,” Bhuyan said.